1. Technical Field of the Invention
The present invention relates to an occupant restraint system in which a side airbag is disposed in a folded state along an upper edge of a door opening of a vehicle body, the airbag is inflatable by a gas, generated by an inflator, when the vehicle is involved in a side collision. Upon inflation, the airbag is deployed into a curtain shape along the inner face of a side of an occupant compartment. When the vehicle is involved in either a front collision or a side collision, a pre-tensioner applies a tension to a shoulder belt of a seat belt system for restraining an occupant in a seat.
2. Description of the Related Art
An occupant restraint system in which an airbag is deployed into a curtain shape along the inner face of a side of an occupant compartment when the vehicle is involved in a side collision is known in, for example, Japanese Patent Application Laid-open Nos. 2000-33847 and 11-235965. With regard to a seat belt system, there is known art in which a shoulder belt can normally be drawn from a retractor so that the body of an occupant is not restrained from moving and, when the vehicle is involved in a front collision, a pre-tensioner provided in the retractor draws in the shoulder belt so as to apply a tension thereto, thereby reliably restraining the occupant in a seat.
However, since the pre-tensioner of the known seat belt system does not operate when the vehicle is involved in a side collision, if the airbag deploys downward along the inner face of a side of the occupant compartment in this state, depending on the positional relationship between a seat belt anchor and the occupant, there is a case where the lower edge of the air bag might interfere with the shoulder belt of the seat belt system, and there is a possibility that the shoulder belt might be displaced.
The present invention has been achieved in view of the above-mentioned circumstances, and it is an object of the present invention to maintain a correct positional relationship between the occupant and the shoulder belt of the seat belt system when the side air bag deploys downward along the inner face of a side of the occupant compartment.